Vehicle heat exchanger assembly

ABSTRACT

A vehicle heat exchanger assembly includes first and second heat exchangers including first and second heat exchange units, respectively, a blower and a fan shroud. The blower causes air to flow from the first heat exchanger to the second heat exchanger, and is arranged in an air passage formed in a space between the first and second heat exchange units. The fan shroud has an enclosing wall part disposed on an external periphery of the blower to substantially enclose the air passage formed between the first heat exchanger and the second heat exchanger, a support part supporting the blower, and a plurality of support stays extending from the support par toward the enclosing wall part to connect the support part and the enclosing wall part.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Japanese Patent Application No.2010-136468 filed on Jun. 15, 2010. The entire disclosure of JapanesePatent Application No. 2010-136468 is hereby incorporated herein byreference.

BACKGROUND

1. Technical Field

The present invention relates to a vehicle heat exchanger assemblyprovided with a plurality of heat exchangers that cool a cooling mediumthat flows through the heat exchangers using air blown by a cooling fan.

2. Related Art

The vehicle heat exchanger assembly is composed of a single heatexchanger (e.g., only a radiator for cooling an engine) or a pluralityof heat exchangers (e.g., a radiator and air conditioner) mounted in avehicle. In this case, the manner in which required cooling ability isassured is important in order to efficiently cool the heat exchangers ina wide range of engine operation such as engine idling and high-speedtravel. For this reason, the following conventional placements,mountings, and other arrangements of the heat exchangers and coolingfans have been made.

In a conventional vehicle heat exchanger assembly, two different heatexchangers, i.e., a radiator and a cooler condenser are arranged in thevehicle front and rear, respectively, and the external peripheralportions of the heat exchangers are connected together by a cylindricalcooling-air guide plate. A shroud is provided to the cooling-air guideplate in the lateral directions or in the left or right direction of thevehicle body, and an opening is provided in the shroud in which acooling fan is disposed so as to draw air into the shroud via the heatexchangers. The airflow is discharged from the aperture toward widthdirection of the vehicle body to directly cause air inside the enginecompartment to flow while neither of the heat exchangers use air thathas flowed through the other heat exchanger (e.g., see JapaneseLaid-Open Utility Model Application Publication No. 63-190517).

Another conventional vehicle heat exchanger assembly is a multi-passheat exchanger that uses a two-path cross-flow system in which a sharedengine coolant or the like flows in a parallel flow or a U-turn flowbetween a first heat exchanger (rearward placement) and a second heatexchanger (forward placement) in which the air flow surfaces arearranged substantially in parallel fashion; and an air fan unit isdisposed in an air gap between the first heat exchanger and the secondheat exchanger (e.g., see Japanese Laid-Open Patent ApplicationPublication No. 2005-76560). The air fan unit is composed of arectangular parallelepiped shroud case, circular apertures that matchthe circular shape of the cooling fans are provided in the front andrear surfaces where cooling fans are arranged facing each other, and airis made to flow in a uniform fashion to the heat exchangers.

In yet another conventional vehicle heat exchanger assembly, twodifferent heat exchangers such as a radiator, an oil cooler, or the likeare housed in a cooling package main body. The cooling package main bodyis composed of a quadrangular frame that covers the external peripheralside of the heat exchangers, large quadrangular apertures are providedin the front and rear surfaces, and long members are made to extend fromthe frame corners toward the motor support member in the aperture centerposition. A cooling fan drive motor is mounted on the motor supportmember on the external surface of the cooling package main body, arotating shaft of the motor protrudes in the opposite direction apertureplane, and a cooling fan is mounted on the distal end of the rotatingshaft, whereby the cooling fan is set at a distance from the coolingpackage main body to improve the suction ability of the cooling fan. Ashroud is provided surrounding the cooling fan from the aperture plane,and a fan guard is disposed on the outside thereof (e.g., see JapaneseLaid-Open Patent Application Publication No. 2008-190513).

Yet another conventional vehicle heat exchanger assembly is one in whicha radiator is used, and a fan shroud is mounted directly on the two endparts of upper and lower tanks of the radiator using four mounting staysintegrally formed with the fan shroud (e.g., see Japanese Laid-OpenUtility Model Application Publication No. 03-37234).

A cylindrical shell is integrally formed with a fan shroud together witha cooling fan, the upper portion of the fan shroud covers the heatexchanger part of the radiator, and the lower portion of the fan shroudis formed with an opening. Holes for travel-induced airflow are formedin the mounting stays of the lower portion so that air is allowed toflow.

SUMMARY

However, the conventional heat exchangers for a vehicle described abovehave the following problems.

First, with the vehicle heat exchanger assembly described in JapaneseLaid-Open Utility Model Application Publication No. 63-190517, air thathas passed through one heat exchanger does not pass by the other heatexchanger to provide cooling. The air inside the engine room can be madeto flow directly to and pass by both heat exchangers, and there is acorrespondingly improved cooling effect. However, since the vanes of thecooling fan are arranged so as to extend in the front-rear direction ofthe vehicle, the radiator and condenser cannot be set at a considerabledistance from each other in the front-rear direction of the vehicle, andthe heat exchange system overall is increased in size, which imposesconsiderable restrictions on the onboard layout. The cooler condenser onthe engine side draws in the high-temperature air in the enginecompartment as well as high-temperature air on the engine side becauseram pressure is not generated during engine idling while the vehicle isstopped or traveling at very low speed. There is a problem in this casein that high cooling capacity cannot be obtained in the cooler condenserwhen the air conditioner is operating.

Air passes through the second heat exchange unit on the upstream side inthe vehicle heat exchanger assembly described in Japanese Laid-OpenPatent Application Publication No. 2005-76560, and the flow of air inthe first heat exchange unit on the downstream side is made uniform.Therefore, the front and rear surfaces of the shroud case have acircular opening that conforms to the cooling fan, and other portionshave a shape that covers the heat exchanger. For this reason, there is aproblem in that travel-induced airflow cannot be sufficiently utilizedwhen the vehicle is traveling, and the front and rear surfaces of theshroud case interferes with and creates resistance to the flow of air tothe heat exchange unit in areas other than the opening. Also, since thefirst heat exchanger and the second heat exchanger are the same type ofheat exchanger (a radiator or the like) having the same purpose, eitherthe first heat exchanger or the second heat exchanger is present betweenthe condenser and the cooling fan in the case that a heat exchangerhaving a different purposed such as a condenser for an air conditionermust be added. Therefore, the cooling capacity of the condenser isconsiderably reduced during engine idling while the vehicle is stoppedor when traveling at very low speed.

In the vehicle heat exchanger assembly described in Japanese Laid-OpenPatent Application Publication No. 2008-190513, the cooling fan must beset at a certain distance in the forward direction away from the heatexchange unit in order to increase the air-suction force of the coolingfan, and there is a problem in that the size of the system overall isincreased in the front-rear direction. Also, the oil cooler is affectedby heat released from the radiator because the radiator, oil cooler, andother heat exchangers are arranged adjacent to each other. As a result,the cooling capacity of the oil cooler is considerably reduced due toheat from the radiator in the case that a shovel or the like is usedduring engine idling while the vehicle is stopped or traveling at verylow speed.

In the vehicle heat exchanger assembly described in Japanese Laid-OpenUtility Model Application Publication No. 03-37234, a fan shroud isdirectly mounted on the radiator tanks and cooling fans are made to faceeach other near the heat exchanger, the length in the front-reardirection of the vehicle can be reduced, and travel-induced airflow ismore readily used due to the setting of the aperture in the lower partand the travel-induced airflow through-holes of the mounting stays.However, there are gaps in the front-rear direction of the vehiclebetween the heat exchangers and the cylindrical shell that houses thecooling fans. Therefore, a problem is presented in that, during engineidling when the vehicle is stopped, a portion of the air does not passthrough the heat exchange unit and is taken in by the cooling fan fromthe external peripheral side, or passes through the cooling fan and isthen blown back and taken into the cooling fan by way of the gaps fromthe external peripheral side of the cooling fan; and the coolingcapacity of the heat exchangers is reduced by a commensurate amount.

The present invention was devised in view of the above, it being anobject thereof to provide a vehicle heat exchanger assembly providedwith a first heat exchanger and a second heat exchanger, wherein theairflow resistance produced between the heat exchangers can be reduced,and the effect of heat from one heat exchanger on the other heatexchanger can be suppressed.

A vehicle heat exchanger assembly according to one aspect of the presentinvention includes a first heat exchanger, a second heat exchanger, ablower and a fan shroud. The first heat exchanger has a first heatexchange unit that allows air to pass therethrough. The second heatexchanger is arranged on a downstream side of the first heat exchangerwith respect to an air flow direction. The second heat exchanger has asecond heat exchange unit arranged parallel to the first heat exchangeunit to allow air to pass therethrough. The blower is configured andarranged to cause air to flow from the first heat exchanger to thesecond heat exchanger, the blower arranged in an air passage formed in aspace between the first heat exchange unit and the second heat exchangeunit. The fan shroud has an enclosing wall part, a support part and aplurality of support stays. The enclosing wall part is disposed on anexternal periphery of the blower to substantially enclose the airpassage formed between the first heat exchanger and the second heatexchanger. The support part supports the blower. The support staysextend from the support par toward the enclosing wall part to connectthe support part and the enclosing wall part.

In the vehicle heat exchanger assembly of the present invention, it ispossible to suppress a reduction in cooling capacity of the two heatexchangers by reducing airflow resistance produced by a shroud or thelike between the heat exchangers when ram pressure is generated by,e.g., travel, and by making use of travel-induced airflow. Even duringengine idling when the vehicle is stopped or traveling at very lowspeed, it is possible to reduce the effect that the heat produced by anair conditioner or another heat exchanger has on the radiator or anotherheat exchanger.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the attached drawings which form a part of thisoriginal disclosure:

FIG. 1 is a top plan view showing a vehicle heat exchanger assembly of afirst embodiment of the present invention;

FIG. 2 is a side view of a partial cross section of the first embodimentof the present invention;

FIG. 3 is an exploded perspective view as seen from the rear of avehicle and shows the vehicle heat exchanger assembly of the firstembodiment of the present invention;

FIG. 4 is a front view of the fan shroud part of the vehicle heatexchanger assembly of a second embodiment of the present invention;

FIG. 5 is front view showing the fan shroud part of the vehicle heatexchanger assembly of a third embodiment of the present invention;

FIG. 6 is an enlarged cross-sectional view along the line 6-6 of FIG. 5;and

FIG. 7 is an enlarged perspective view as seen from the rear of avehicle and shows a structure of the non-return valve of the thirdembodiment of the present invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Embodiments of the present invention are described in detail below withreference to the examples shown in the drawings.

First Embodiment

First, the overall configuration of the first embodiment will bedescribed.

The heat exchanger of the first embodiment is mainly composed of acondenser 1 as a first heat exchanger, a radiator 2 as a second heatexchanger, a motor fan 3 as a blower, and a fan shroud 4 for supportingthe motor fan, as shown in FIGS. 1 and 2. The above are integrallymounted in the front-rear direction of the vehicle in the sequence ofthe condenser 1, the fan shroud 4 that supports the motor fan 3, and theradiator 2 from the front side of the vehicle, and the assembly issupported by the vehicle body by a radiator-core support (not shown).

The condenser 1 as the first heat exchanger is used as an airconditioner, and is provided with a first heat exchange unit (condensercore) 11 through which air can flow in the front-rear direction of avehicle, a left-side tank 12 and right-side tank 13 mounted on the left-and right-side ends, respectively, and a liquid tank (not shown) mountedon the side surface in the forward area of the left-side tank 12, asshown in FIG. 3.

The first heat exchange unit 11 has a plurality of tubes 11 a throughwhich a cooling medium flows between the tanks 12, 13 and of which thetwo end parts are connected to the left-side tank 12 and the right-sidetank 13, respectively; and corrugated fins 11 b mounted between theadjacent tubes 11 a, 11 a. The upper and lower ends of the left andright tanks 12, 13 are connected to each other by a reinforcement 14. Acooling medium intake port P1 is provided to the upper-side part in theupper area of the right-side tank 13, and an outlet port Q2 is providedto a lower area.

The radiator 2 as the second heat exchanger is used for cooling theengine, and is disposed parallel to the first heat exchange unit 11 ofthe condenser 1 in the rear of the vehicle, which is the downstream sideof the condenser 1. The radiator 2 is provided with a second heatexchanger (radiator core) 21 through which air can flow in thefront-rear direction of the vehicle, and a left-side tank 22 andright-side tank 23 mounted on the left- and right-side ends,respectively.

The second heat exchanger 21 has a plurality of tubes 21 a through whicha cooling medium flows between the tanks 22, 23, the two end parts ofthe tubes 21 a being connected to the left-side tank 22 and theright-side tank 23, respectively; and corrugated fins 21 b mountedbetween the adjacent tubes 21 a, 21 a. The upper and lower ends of theleft and right tanks 22, 23 are connected to each other by areinforcement 15. A cooling medium intake port Q1 that protrudesrearward is provided to the upper portion of the right-side tank 23, andan outlet port PQ that protrudes rearward is provided to a lower portionof the left-side tank 22.

In this embodiment, the first heat exchange unit 11 of the condenser 1is configured and arranged to receive a cooling medium having atemperature lower than a temperature of a cooling medium that flows inthe second heat exchange unit 21 of the radiator 2.

The motor fan 3 as a blower causes a cooling fan to rotate using anelectric motor 31 so as to cause air to flow from the condenser 1 towardthe radiator 2, and is configured such that a fan 32 having four vanesis mounted on a fan axis FA (the rotating shaft) of the electric motor31. The fan 32 has the distal ends of each vane connected to a ring 33,which forms the external peripheral portion of the fan 32.

The motor fan 3 configured in the manner described above is disposed inan air passage 5 (described further below) formed in the interior spaceof the fan shroud 4, which is arranged between the condenser 1 and theradiator 2.

The fan shroud 4 links the areas between the condenser 1 and theradiator 2, and the motor fan 3 is accommodated in and covered by thefan shroud 4.

The fan shroud 4 is made of resin and has a enclosing wall part 41 forcovering the external periphery of the motor fan 3, a support part 42for supporting the electric motor 31 of the motor fan 3, and foursupport stays 43 that extend outward in the radial direction from thesupport part 42 to the enclosing wall part 41 and connect the supportpart 42 and the enclosing wall part 41. It is preferred that the supportstays 43 have to the extent possible a reduced width on the side withwhich the airflow makes contact and that the length in the depthdirection (corresponding to the axial direction of the electric motor31) be increased by a commensurate amount in order to assure sufficientstrength while reducing airflow resistance.

The enclosing wall part 41 of the fan shroud 4 is arranged so as toconnect the areas between the external periphery of the first heatexchange unit 11 of the condenser 1 and the external periphery of thesecond heat exchanger 21 of the radiator 2. The space inside theenclosing wall part 41 forms an air passage 5 for directing air that haspassed through the condenser 1 to the radiator 2.

In the present example, the air passage 5 has a ventilationcross-sectional area that is substantially equal in size to thecross-sectional area in the ventilation direction of the space (thespace enclosed by the dash-dot line S in FIG. 3) formed by theconnection between the external periphery of the first heat exchangeunit 11 and the external periphery of the second heat exchanger 21, anddoes not narrow inward (the ventilation cross-sectional area is notgreatly reduced) at an intermediate point.

The enclosing wall part 41 of the fan shroud 4 has left and rightsidewalls 41 a, 41 b that extend in the horizontal direction, and anupper wall 41 c and lower wall 41 d that extend in the verticaldirection and connect the upper and low ends of the left and rightsidewalls 41 a, 41 b together to form a tubular member defining anopening 46, as shown in FIG. 3. In this embodiment, the tubular memberformed by the left and right sidewalls 41 a, 41 b and the upper andlower walls 41 c, 41 d has a center axis that substantially coincidesthe fan axis FA of the fan 32. As mentioned above, the air passage 5enclosed by the tubular member does not narrow inward. In other words,the tubular member has a rectangular cross-sectional shape taken along aplane perpendicular to the fan axis FA of the fan 32 which issubstantially constant along the fan axis FA as shown in FIGS. 1-3. Therectangular cross-sectional shape defined by the left and rightsidewalls 41 a, 41 b and the upper and lower walls 41 c, 41 d has anarea (ventilation cross-sectional area) substantially equal to across-sectional area of the first heat exchange unit 11 of the condenser1 taken along a plane perpendicular to the fan axis FA, and across-sectional area of the second heat exchange unit 21 of the radiator2 taken along a plane perpendicular to the fan axis FA.

The enclosing wall part 41 has extension parts 44 a, 44 b that extendfrom the front edge part of the left and right sidewalls 41 a, 41 b inthe outward width direction of the vehicle and then in forward directionof the vehicle, and that align with the vehicle-rear-facing externalsurface of the left-side tank 12 and the right-side tank 13 of thecondenser 1.

The enclosing wall part 41 also has extension parts 45 a, 45 b thatextend from the rear edge part of the left and right sidewalls 41 a, 41b in the outward width direction of the vehicle and then in rearwarddirection of the vehicle, and that align with the vehicle-front-facingexternal surface of the left-side tank 22 and the right-side tank 23 ofthe radiator 2.

The enclosing wall part 41 has pawl parts 44 c, 44 d that extend fromthe front edge part of the upper wall 41 c and the lower wall 41 d tothe forward direction of the vehicle, and that retain the upper andlower surfaces of the reinforcement 14 disposed in the upper and loweredges of the first heat exchange unit 11 of the condenser 1. Thus, theupper wall 41 c (one example of the first wall portion) covers an upperside (one example of the first side) of the first heat exchange unit 11and an upper side of the second heat exchange unit 21, and the lowerwall 41 d (one example of the second wall portion) covers a lower side(one example of the second side) of the first heat exchange unit 11 anda lower side of the second heat exchange unit 21.

The enclosing wall part 41 has pawl parts 45 c, 45 d that extend fromthe rear edge part of the upper wall 41 c and the lower wall 41 d to therearward direction of the vehicle, and that retain the upper and lowersurfaces of the reinforcement 15 disposed in the upper and lower edgesof the second heat exchanger 21 of the radiator 2.

The vehicle heat exchanger assembly configured in the manner describedabove is integrally assembled in a state in which the condenser 1, thefan shroud 4 for supporting the motor fan 3, and the radiator 2 aresuperimposed in sequence from the front side FR of the vehicle in thefront-rear direction of the vehicle. In their assembled state, the leftand right tanks 12, 13 of the condenser 1 and the extension parts 44 a,44 b that align with a part of the external surfaces thereof are inclose contact, or even if a gap formed therebetween, the gap is formedto be as narrow as possible so that air that flows from an externalspace of the enclosing wall part 41 into the internal space (air passage5) of the enclosing wall part 41 is reduced. Similarly, in theirassembled state, the pawl parts 44 c, 44 d and the reinforcement 14above and below the condenser 1 are in close contact, or even if a gapis formed therebetween, the gap is formed to be as narrow as possible sothat air that flows from an external space of the enclosing wall part 41into the internal space (air passage 5) of the enclosing wall part 41 isreduced.

Similarly, the left and right tanks 22, 23 of the radiator 2 and theextension parts 45 a, 45 b of the enclosing wall part 41 that cover apart of the external surfaces thereof are in close contact, or even if agap is formed therebetween, the gap is formed to be as narrow aspossible so that air that flows from an external space of the enclosingwall part 41 into the internal space (air passage 5) of the enclosingwall part 41 is reduced. Similarly, in their assembled state, the pawlparts 45 c, 45 d and the reinforcement 15 above and below the radiator 2are in close contact, or even if a gap is formed therebetween, the gapis formed to be as narrow as possible so that air that flows from anexternal space of the enclosing wall part 41 into the internal space(air passage 5) of the enclosing wall part 41 is reduced.

Next, the effect of the first embodiment will be described.

Since the speed is zero or very low during engine idling when thevehicle is parked, traveling at very low speed, or the like, thecondenser 1 and the radiator 2 are not expected to be cooled bytravel-induced airflow from the forward direction of the vehicle.Therefore, in such a state, the electric motor 31 is energized and thefan 32 is caused to rotate to forcibly take in external air from theforward area of the condenser 1. The external air is passed through theheat exchanger 11 of the condenser 1, whereby the cooling medium thatflows through the tubes 11 a is cooled by heat exchange via the fins 11b or in part by direct air contact with tubes 11 a.

Air that passes through the condenser 1 passes by the fan 32 and flowsto the second heat exchanger 21 of the radiator 2.

The air that passes through the condenser 1 is directed with slightlyreduced speed to the air passage 5 formed inside the enclosing wall part41 of the fan shroud 4 and moves toward the radiator 2 with goodefficiency.

When the air passes through the second heat exchanger 21 of the radiator2, the cooling medium that flows through tubes 21 a is cooled by heatexchange via the fins 21 b or in part by direct air contact with tubes 1a.

In the case that the condenser 1 and the radiator 2 are cooled, theengine speed is kept low during idling while the vehicle is parked,during very low speed travel, or at other times. Therefore, the amountof heat is not as great in comparison with ordinary travel, but the airconditioner is often used during such times, so the required coolingcapacity of the condenser 1 is increased.

In the vehicle heat exchanger assembly of the first embodiment, thecondenser 1 is cooled to a greater extent than when using air that hasonce passed through the radiator 2 because the condenser 1 is in frontof the radiator 2, and as a result, air is initially sent to thecondenser 1 by the motor fan 3. Therefore, the condenser 1 can besufficiently cooled even when the air conditioner is operated duringidling or very low speed travel. On the other hand, although the airthat passes through the radiator 2 has been warmed once by the condenser1 and has less cooling capacity, the cooling medium that flows throughthe engine during idling in which heat output is low does not have atemperature as high as during ordinary travel, and the radiator 2 istherefore sufficiently cooled.

A portion of the air that passes through the second heat exchanger 21makes contact with the engine and is discharged from below the vehicle.A portion of the air that has made contact with and rebounded from theengine is blown back to the radiator 2 side, and the left and righttanks 22, 23 of the radiator 2, the reinforcement 15, and the extensionparts 45 a, 45 b and pawl parts 45 c, 45 d formed in the enclosing wallpart 41 of the fan shroud 4 are arranged in close contact or with aslight gap. Therefore, the air blown back through the area is returnedfrom the exterior of the enclosing wall part 41 to the front surface ofthe radiator 2 and the cooling capacity of the radiator 2 is notreduced. Similarly, the left and right tanks 12, 13 of the condenser 1,the reinforcement 14, and the extension parts 44 a, 44 b and pawl parts44 c, 44 d are arranged in close contact or with a slight gap.Therefore, the air blown back through the area is returned from theexterior of the enclosing wall part 41 to the front surface of theradiator 2 or motor fan 3, and the cooling capacity of the radiator 2 isnot reduced.

On the other hand, the amount of airflow that passes through thecondenser 1 and the radiator 2 is considerably increased because rampressure is generated in the front portion of the vehicle duringordinary vehicle travel. At this point, the engine generates high heatbecause the engine is operating at higher speed than during idling.However, even when air warmed by cooling the cooling medium in thecondenser 1 is sent to the radiator 2, the amount of air that flowsthrough the second heat exchanger 21 of the radiator 2 increasesdramatically and cooling capacity is therefore considerably increased.Therefore, the condenser 1, as well as the radiator 2, is sufficientlycooled during ordinary high-speed vehicle travel. At this point, theinside of the enclosing wall part 41 of the fan shroud 4 forms an airpassage 5 in the space (the space surrounded by the dash-dot line S)that connects the external peripheral surfaces of the condenser 1 andthe radiator 2 together, and since only the four support stays 43 of themotor fan 3 and fan shroud 4 are present in the air passage 5, the airthat moves from the condenser 1 to the radiator 2 undergoes littleresistance from the fan shroud 4 and cooling of the radiator 2 duringtravel is further enhanced. The motor fan 3 may be caused to rotate asrequired during travel, i.e., only in the case that cooling by rampressure is insufficient.

As described above, the following effects can be obtained in the vehicleheat exchanger assembly of the first embodiment.

(1) In the device of the first embodiment, the condenser 1 and radiator2 are arranged on the upstream side and the downstream side,respectively, a fan shroud 4 having an air passage 5 is providedtherebetween, and a motor fan 3 arranged under support by the supportstays 43 at an intermediate point in the air passage 5. The ventilationcross-sectional area of the air passage 5 formed inside the enclosingwall part 41 of the fan shroud 4, which is arranged so as to connect theareas between the external peripheries of the first heat exchange unit11 and the second heat exchanger 21, is designed so as to remainsubstantially unchanged from the surface areas of the first heatexchange unit 11 and the second heat exchanger 21.

The airflow resistance in the condenser 1 can thereby be reduced and thecondenser 1 as well as the downstream radiator 2 can be sufficientlycooled even when the engine produces high heat during travel when, e.g.,ram pressure is produced during travel in a vehicle heat exchangerassembly provided with a condenser 1 and a radiator 2.

(2) In the case that ram pressure is not generated such as during engineidling or the like when the vehicle is parked or traveling in very lowspeed, the cooling medium of the condenser 1 can be sufficiently cooledby causing the motor fan 3 to rotate even when the air conditioner isbeing operated because the condenser 1 is upstream from the radiator 2.In this case, in comparison with the case in which the condenser isarranged behind the radiator, the condenser airflow amount is increasedby an amount commensurate with the reduction in radiator airflowresistance because the condenser 1 is arranged in front of the radiator2. Therefore, the condenser 1 can be readily cooled.

On the other hand, there is no concern for reduced cooling capacity inthis case even if the radiator 2 is cooled by air warmed by thecondenser 1 because the engine is producing a low amount of heat.

(3) Since the motor fan 3 is disposed between the condenser 1 and theradiator 2, the heat received by the condenser 1 from the radiator 2 canbe reduced. It is therefore possible to prevent the cooling capacity ofthe condenser 1 from degrading.

(4) The enclosing wall part 41 of the fan shroud 4 has extension parts44 a, 44 b that extend so as to align with the vehicle-rear-facingexternal surface of the left-side tank 12 and the right-side tank 13 ofthe condenser 1 from the front edge part of the left and right sidewalls41 a, 41 b of the enclosing wall part 41, and has extension parts 44 a,44 b that extend so as to align with the vehicle-front-facing externalsurface of the left-side tank 22 and the right-side tank 23 of theradiator 2 from the rear edge part of the left and right sidewalls 41 a,41 b of the enclosing wall part 41.

The extension parts 44 a, 44 b, 45 a, 45 b can thereby prevent air blownbackward from the engine side from returning to the front surface of theradiator 2 via gaps between the enclosing wall part 41 of the fan shroud4 and the tanks 12, 13, 22, 23 and prevent a reduction in coolingefficiency of the radiator 2, and also improve air utilizationefficiency.

(5) Pawls 44 c, 44 d extend from the front edge part of the upper andlower walls 41 c, 41 d of the enclosing wall part 41 of the fan shroud 4so as to retain the upper and lower surfaces of the reinforcement 15provided to the upper and lower edges of the first heat exchange unit 11of the condenser 1; and pawls 45 c, 45 d extend from the rear edge partof the upper and lower walls 41 c, 41 d of the enclosing wall part 41 soas to retain the upper and lower surfaces of the reinforcement 16provided to the upper and lower edges of the second heat exchanger 21 ofthe radiator 2.

The pawl parts 44 c, 44 d, 45 c, 45 d can thereby prevent air blownbackward from the engine side from returning to the front surface of theradiator 2 via gaps between the enclosing wall part 41 of the fan shroud4 and the reinforcements 15, 16 and prevent a reduction in coolingefficiency of the radiator 2, and also improve air utilizationefficiency.

(6) The motor fan 3 is covered by the fan shroud around the externalperiphery between the condenser 1 and the radiator 2 and it is thereforepossible to prevent human hands and tools from making contact with themotor fan 3 during maintenance and inspection, and safety can beassured.

(7) Since the tanks of the condenser 1 and the radiator 2 are crimped orotherwise fabricated in a conventional manner, the crimped portions arearranged so as to avoid contact with each other in the case that theradiator is arranged on the downstream side of the condenser and themotor fan is disposed on the downstream side of the radiator and thecondenser. Therefore, the gap between the condenser and the radiator areunavoidably enlarged. However, in the first embodiment, the entire heatexchanger can be made more compact in terms of the length (depth) in thefront-rear direction of the heat exchanger because the motor fan 3 isdisposed between the condenser and the radiator and the condenser 1 andthe radiator 2 are arranged so as to be connected by the fan shroud 4.

Other examples will be described next. Illustration or description ofthe same constituent elements having the same reference numerals as thefirst embodiment are omitted in the description of the other examples,and only points of difference will be described.

Second Embodiment

Referring now to FIG. 4, a vehicle heat exchanger assembly in accordancewith a second embodiment will now be explained. In view of thesimilarity between the first and second embodiments, the parts of thesecond embodiment that are identical to the parts of the firstembodiment will be given the same reference numerals as the parts of thefirst embodiment. Moreover, the descriptions of the parts of the secondembodiment that are identical to the parts of the first embodiment maybe omitted for the sake of brevity.

The second embodiment shows another example of the fan shroud portion inthe first embodiment, and FIG. 4 is a front view showing the fan shroudpart of the vehicle heat exchanger assembly of the second example.

The vehicle heat exchanger assembly of the second embodiment isdifferent from the first embodiment described above in that the portionaround a circular ventilating aperture 47 for directing air blown by themotor fan is blocked by a panel member 48 inside the frame of theenclosing wall part 41 in the fan shroud 4. However, the interior of theenclosing wall part 41 of the fan shroud 4 has the same size and shapeas the first embodiment on the upstream and downstream sides of theventilating aperture 47.

Therefore, in the second embodiment, the airflow resistance in the fanshroud 4 is slightly increased in the effect (1) of the firstembodiment, but the following effect can be obtained in addition to thesame effect as the first embodiment.

(8) Since the portions other than the ventilating aperture 47 areblocked, it is possible to further prevent backflow of heat from theradiator 2 side to the condenser 1 side in comparison with the firstembodiment. Reduction in the cooling efficiency of the condenser 1 canthereby be prevented.

Third Embodiment

Referring now to FIGS. 5 to 7, a vehicle heat exchanger assembly inaccordance with a third embodiment will now be explained. In view of thesimilarity between the second and third embodiments, the parts of thethird embodiment that are identical to the parts of the secondembodiment will be given the same reference numerals as the parts of thesecond embodiment. Moreover, the descriptions of the parts of the thirdembodiment that are identical to the parts of the second embodiment maybe omitted for the sake of brevity.

The third embodiment shows a modified example of the fan shroud portionin the second embodiment. FIG. 5 is a front view showing the fan shroudpart of the vehicle heat exchanger assembly of the third embodiment.FIG. 6 is an enlarged cross-sectional view along the line 6-6 of FIG. 5.FIG. 7 is a perspective view as seen from the rear of a vehicle andshows the main part of the third embodiment.

Flow from the condenser 1 side to the radiator 2 side is allowed in thefour corners in portions other the ventilating aperture 47 in the panelmember 48 of the fan shroud 4, but the vehicle heat exchanger assemblyof the third embodiment is different from the second embodiment in thata communication aperture 50 has a non-return valve 49 that preventsbackflow from the radiator 2 side to the condenser 1 side.

In other words, the ventilating aperture 47 for directing air blown fromthe motor fan 3 is disposed substantially in the center of the panelmember 48 that blocks the area within the frame of the enclosing wallpart 41 in the fan shroud 4, and the communication aperture 50 isdisposed in each of the four corners away from the ventilating aperture47 in the panel member 48.

The non-return valve 49 blocking the communication aperture 50 from theradiator 2 side is provided to the upper-side aperture edge part of eachcommunication aperture 50 and is capable of rotating about the center ofa hinge part 51 formed in the upper-side aperture edge part.

The non-return valve 49 has a bottom plate part 49 b that folds towardthe communication apertures 50 in the lower edge part of the bottomplate part 49 b which has a width sufficient to close off thecommunication aperture 50. Left and right sidewall parts 49 c, 49 c forblocking a triangular portion formed by a line connecting the upper endof a plate-shaped flap 49 a and the distal ends of the bottom plate part49 b are formed in the left and right edge parts of the bottom platepart 49 b and the plate-shaped flap 49 a.

In the vehicle heat exchanger assembly of the third embodiment, theconfiguration described above produces a state in which thecommunication aperture 50 is blocked by the weight of the non-returnvalve 49, as shown by the solid line representation in FIG. 6, when thevehicle is stopped or idling, and the heated air of the radiator 2 sideis prevented from flowing to the condenser 1 side. Reduction in thecooling efficiency of the condenser 1 can thereby be prevented.

The non-return valve 49 is opened to the radiator 2 side by the pressureof travel-induced airflow, as shown by the dashed line in FIG. 6, whenthe vehicle is traveling. Therefore, the travel-induced airflow passedthrough to the radiator 2 side with good efficiency. Cooling efficiencyof the radiator 2 can thereby be improved.

The present invention was described above on the basis of examples, butthe present invention is not limited to these examples; designmodifications or the like can be performed within a range that does notdepart from the spirit of the present invention.

The examples describe a case in which the first heat exchanger is acondenser and the second heat exchanger is a radiator, but the firstheat exchanger may be a radiator and the second heat exchanger may be acondenser. The heat exchangers may both be radiators or another heatexchanger. In such instances it is sometimes the case that, when asecond heat exchanger is disposed at least on the downstream side, in ahybrid automobile that is operated using an engine and an electric motoras power sources, the temperature of the cooling medium in the heatexchanger on the engine side is lower than in the heat exchanger forcooling the inverter on the electric motor side during engine idlingwhile the vehicle is stopped or during travel at very low speed. In anelectric automobile, there is no engine power source and therefore noradiator, but an inverter is used because the vehicle is operated by anelectric motor as the power source. In such cases, for example, a heatexchanger for cooling the inverter, and a condenser for the airconditioner must be arranged.

Therefore, the second heat exchanger is preferably arranged on thedownstream side as the heat exchanger having less cooling capacity thanthe first heat exchanger.

There has been described a case in which tanks have been provided to theleft and right of the condenser and the radiator, but it is alsopossible to apply the present invention to cases in which the tanks areprovided above and below.

Also, the extension parts and pawl parts formed in the enclosing wallpart of the fan shroud may be provided so as to conform to a portion ofthe inlet pipe and outlet pipe of the heat exchangers as required.

GENERAL INTERPRETATION OF TERMS

In understanding the scope of the present invention, the term“comprising” and its derivatives, as used herein, are intended to beopen ended terms that specify the presence of the stated features,elements, components, groups, integers, and/or steps, but do not excludethe presence of other unstated features, elements, components, groups,integers and/or steps. The foregoing also applies to words havingsimilar meanings such as the terms, “including”, “having” and theirderivatives. Also, the terms “part,” “section,” “portion,” “member” or“element” when used in the singular can have the dual meaning of asingle part or a plurality of parts. Finally, terms of degree such as“substantially”, “about” and “approximately” as used herein mean areasonable amount of deviation of the modified term such that the endresult is not significantly changed. For example, these terms can beconstrued as including a deviation of at least ±5% of the modified termif this deviation would not negate the meaning of the word it modifies.

While only selected embodiments have been chosen to illustrate thepresent invention, it will be apparent to those skilled in the art fromthis disclosure that various changes and modifications can be madeherein without departing from the scope of the invention as defined inthe appended claims. Furthermore, the foregoing descriptions of theembodiments according to the present invention are provided forillustration only, and not for the purpose of limiting the invention asdefined by the appended claims and their equivalents.

1. A vehicle heat exchanger assembly comprising: a first heat exchangerhaving a first heat exchange unit that allows air to pass therethrough;a second heat exchanger arranged on a downstream side of the first heatexchanger with respect to an air flow direction, the second heatexchanger having a second heat exchange unit arranged parallel to thefirst heat exchange unit to allow air to pass therethrough; a blowerconfigured and arranged to cause air to flow from the first heatexchanger to the second heat exchanger, the blower arranged in an airpassage formed in a space between the first heat exchange unit and thesecond heat exchange unit; and a fan shroud having an enclosing wallpart disposed on an external periphery of the blower to substantiallyenclose the air passage formed between the first heat exchanger and thesecond heat exchanger, a support part supporting the blower, and aplurality of support stays extending from the support part toward theenclosing wall part to connect the support part and the enclosing wallpart.
 2. The vehicle heat exchanger assembly according to claim 1,wherein each of the first heat exchanger and the second heat exchangerhas a plurality of tanks, and the fan shroud has a plurality ofextension parts arranged at positions corresponding to at least a partof the tanks to restrict air flow through a gap between the enclosingwall part and the tank.
 3. The vehicle heat exchanger assembly accordingto claim 1, wherein the first heat exchange unit of the first heatexchanger is configured and arranged to receive a cooling medium havinga temperature lower than a temperature of a cooling medium that flows inthe second heat exchange unit of the second heat exchanger.
 4. Thevehicle heat exchanger assembly according to claim 2, wherein the firstheat exchange unit of the first heat exchanger is configured andarranged to receive a cooling medium having a temperature lower than atemperature of a cooling medium that flows in the second heat exchangeunit of the second heat exchanger.
 5. The vehicle heat exchangerassembly according to claim 1, wherein the blower includes a fan, andthe enclosing wall part of the fan shroud has a tubular member with arectangular cross-sectional shape taken along a plane perpendicular to afan axis of the blower.
 6. The vehicle heat exchanger assembly accordingto claim 5, wherein the rectangular cross-sectional shape of the tubularmember is substantially constant along the fan axis, and has an areasubstantially equal to a cross-sectional area of the first heat exchangeunit of the first heat exchanger taken along a plane perpendicular tothe fan axis.
 7. The vehicle heat exchanger assembly according to claim6, wherein the area of the rectangular cross-sectional shape of thetubular member is also substantially equal to a cross-sectional area ofthe second heat exchange unit of the second heat exchanger taken along aplane perpendicular to the fan axis.
 8. The vehicle heat exchangerassembly according to claim 5, wherein the tubular member of theenclosing wall part has first and second wall portions facing eachother, the first wall portion covering a first side of the first heatexchange unit and a first side of the second heat exchange unit, and thesecond wall portion covering a second side of the first heat exchangeunit and a second side of the second heat exchange unit.
 9. The vehicleheat exchanger assembly according to claim 1, wherein the blowerincludes a fan, and the enclosing wall part includes a tubular memberwith a center axis extending in a direction parallel to a fan axis ofthe blower, and a panel member extending along a plane perpendicular tothe fan axis of the blower, the panel member defining a circularventilating aperture formed around the fan.
 10. The vehicle heatexchanger assembly according to claim 9, wherein the panel memberincludes at least one communication aperture and a non-return valveconfigured and arranged to allow air flow in a direction from the firstheat exchanger to the second heat exchanger through the at least onecommunication aperture and to prevent air flow in a direction from thesecond heat exchanger to the first heat exchanger.